This invention relates generally to cosmetic preparations and more particularly to universally usable w/o emulsion bases.
From the physicochemical perspective, cosmetic preparations, such as creams and lotions for example, are emulsions of which there are two types, namely: water-in-oil (w/o) and oil-in-water (o/w) emulsions. Commercially, there is a particular interest in w/o emulsions which can differ greatly in their viscosity from solid creams through soft creams to thinly liquid lotions. An enormous number of suitable oil components, emulsifiers and auxiliaries and additives is available to the cosmetic chemist for the production of such preparations, his task being to combine them in such a way that a product with the requisite range of applications is obtained. This is sometimes a very laborious task, particularly when the goal is to produce products with a specific viscosity which they are able to retain for long periods, even when stored at elevated temperature, without becoming thinly liquid, gelling or separating. Another important requirement in the formulation of w/o emulsions is to adjust the sensorial properties of the emulsions to suit the user. A particular requirement in this regard is to combine oil components differing in polarity and spreading with one another in such a way that a so-called xe2x80x9cspreading cascadexe2x80x9d is formed [cf. U. Zeidler in Fette, Seifen, Anstrichmitt. 87, 403 (1985) and S. Wallat et al. in Parf. Kosm. 75, 768 (1994)]. Unfortunately, the oils are often difficult to incorporate together in a stable form because of their different polarities.
International patent application WO 95/34528 discloses w/o emulsions containing polyolpolyhydroxystearates. Other auxiliaries and additives which may be added include inter alia co-emulsifiers, such as for example citric acid esters, sorbitan esters, etc., fats and waxes and stabilizers, such as metal salts of fatty acids.
Accordingly, the complex problem addressed by the invention was to provide mixtures which, on the principle of a simple building block, would allow the production of storage-stable w/o emulsions differing in their viscosities and, at the same time, would also enables oils of different polarity to be incorporated.